There is more than one type of wrongful termination under the law, and the statute of limitations depends on the type of case you believe you have.
If it is an EEOC case, as described above, you have 180 days (300 days in some states) from the most recent instance of discrimination/harassment to file a complaint with the EEOC. Somewhere between six months and two years after that, you will receive a right to sue letter, and you have 90 days from the receipt of the right to sue letter to file a lawsuit.
If, however, you have a wrongful termination claim due to FMLA issues, or workers comp issues, or union activity issues, or something else altogether, then the SOL can be quite different.
Why do you believe that your termination was wrongful? It makes a difference, as you can see.